https://doi.org/10.25085/rsea.790204

ARTICULOS

Taxonomic studies on the subgenus Megachile ( Dactylomegachile) in Argentina (Hymenoptera: Megachilidae)

Estudios taxonómicos del subgénero Megachile (Dactylomegachile) en Argentina (Hymenoptera: Megachilidae)

 

Silvana P. DURANTE

Juan P. TORRETTA

Nora C CABRERA

Arturo ROIG-ALSINA1

 

1 Universidad de Buenos Aires, Facultad de Agronomía, Cátedra de Botánica General. Buenos Aires, Argentina. * E-mail: torretta@agro.uba.ar

2 Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina.

3 División Entomología, Museo de La Plata. La Plata, Argentina.

4 Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”. Buenos Aires, Argentina.

 

Received 21 - XII - 2019

Accepted 04 - V - 2020

Published 29 - VI - 2020

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RESUMEN:

Esta contribución trata las especies más comunes y frecuentemente colectadas de Megachile ( Dactylomegachile) en Argentina. Se esclarece la taxonomía de siete especies, presentando asociaciones de sexos para todas menos para M. binota, cuyo macho permanece desconocido. En la mayoría de los casos las asociaciones de sexos se basan en ejemplares criados de nidos trampa. Se proponen las siguientes nuevas sinonimias: M. nigella Vachal es sinónimo posterior de M. ctenophora Holmberg; M. parsonsiae Schrottky y M. riojanensis Mitchell son sinónimos posteriores de M. infima Vachal; M. trochantina Vachal y M. perspicua Mitchell son sinónimos posteriores de M. leucografa Friese; M. albopunctata Jörgensen es sinónimo posterior de M. tetrazona Friese; M. suspecta Vachal y M. impudens Mitchell son sinónimos posteriores de M. vagata Vachal. Se presentan redescripciones, datos de distribución y una clave para las especies tratadas.

PALABRAS CLAVE. Abejas cortadoras de hojas. Abejas silvestres. Argentina. Taxonomía.

ABSTRACT:

This contribution deals with the most common and frequently collected species of Megachile ( Dactylomegachile) in Argentina. The taxonomy of seven species is clarified, presenting sex associations for all but one of the species, M. binota, the male sex of which remains unknown. In most cases sex associations are based on specimens reared from trapnests. The following new synonymies are proposed: M. nigella Vachal is a junior synonym of M. ctenophora Holmberg; M. parsonsiae Schrottky and M. riojanensis Mitchell are junior synonyms of M. infima Vachal; M. trochantina Vachal and M. perspicua Mitchell are junior synonyms of M. leucografa Friese; M. albopunctata Jörgensen is a junior synonym of M. tetrazona Friese; M. suspecta Vachal and M. impudens Mitchell are junior synonyms of M. vagata Vachal. Redescriptions, distributional data, and a key to the studied species are given.

KEYWORDS. Argentina. Leafcutter bees. Taxonomy. Wild bees.

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INTRODUCTION

The genus Megachile Latreille is widely distributed in temperate and tropical areas of the world, with great diversity in the Neotropical region (Michener, 2007; Moure et al., 2007; Raw, 2007). This genus is easy to recognize, but identification of its subgenera is often difficult. Mitchell revised the New World fauna and subdivided the genus into numerous subgenera; he described (1943) five neotropical subgenera, including Chrysosarus and Dactylomegachile. Mitchell (1980) newly revised the genus and proposed a different arrangement; he divided Megachile into genera, one of them Chrysosarus, with Dactylomegachile as a subgenus. Michener (2000) recognized Megachile as a single genus and grouped the subgenera into three informal groups, assigning Chrysosarus to “Group 1” and including Dactylomegachile as a synonym of Chrysosarus. This status was accepted by various authors (Raw, 2002, 2007; Carvalho & Raw, 2005; Moure et al., 2007; González, 2008). However, Silveira et al. (2002) considered both Chrysosarus and Dactylomegachile as valid subgenera. Durante & Cabrera (2009) tested the monophyly of Chrysosarus and Dactylomegachile using cladistic methodology. According to the results of these authors, these two subgenera can be interpreted as two closely related, although independent clades. González (2013) commented on Chrysosarus, considering that Dactylomegachile, Austrosarus Raw, Stelodides Moure, and Zonomegachile Mitchell are better interpreted as synonyms of this subgenus. However, González et al. (2018) recognized Zonomegachile as a valid subgenus and presented a cladogram showing representatives of Chrysosarus, Dactylomegachile and Stelodides not forming a monophyletic group. The subgenus Dactylomegachile is treated here as defined by Mitchell (1943) and Durante & Cabrera (2009).

The main objective of this contribution is to provide a first approach to the systematics of Dactylomegachile, clarifying the identity of numerous species, proposing new synonymies, giving distributional data, and presenting a key to the studied species.

MATERIAL AND METHODS

Morphological terminology follows Michener (2007), except that Mitchell (1980) is followed for terminology of the hidden sterna of the male. The maximum diameter of the median ocellus (MOD) is used as a reference to express the length of the pubescence and other structures, and the diameter of punctures (PD) to indicate the size of the intervals between the punctures. The metasomal terga (T) and sterna (S) are identified with Arabic numerals. The sex of the specimens is indicated by F, female, and M, male.

Individuals studied are deposited in the following institutions: Cátedra de Botánica General, Facultad de Agronomía, Universidad de Buenos Aires (FAUBA), Buenos Aires, Argentina; Instituto Argentino de Investigaciones de Zonas Áridas (IADIZA), Mendoza, Argentina; Museo Argentino de Ciencias Naturales Bernardino Rivadavia (MACN), Buenos Aires, Argentina; Museum of Comparative Zoology (MCZ), Harvard University, Cambridge, Massachusetts, USA; Museo de La Plata (MLP), La Plata, Argentina; Museum National d'Histoire Naturelle (MNHN), Paris, France; The Natural History Museum (NHMUK), London, United Kingdom; Snow Entomological Collection (SEMC), Lawrence, Kansas, USA; Zoologisches Museum, Museum für Naturkunde der Humbolt Universität (ZMB), Berlin, Germany. Acronyms are used to indicate depositories of the specimens.

RESULTS

Genus MegachileLatreille

Subgenus DactylomegachileMitchell

Type species: Megachile parsonsiaeSchrottky

Diagnosis Diagnosis. The subgenus Dactylomegachile is distinguished by the following combination of characters: antenna, wing venation and tegula black to brown; female mandible 4-dentate, without cutting edges, fourth tooth truncate or incised; female T6 generally straight in profile and apically truncate; female S6 homogeneously covered by scopal hairs; male mandible 3-dentate, with angle on inferior margin; male front coxa glabrous, with short spine and with group of ferruginous bristles; male front tarsus flattened, not excavated anteriorly, pale, with black spot on under surface; male T6 with preapical carina usually denticulate.

Megachile ( Dactylomegachile) binota Vachal Megachile binota Vachal, 1908: 225 (Holotype female, Argentina, Mendoza, MNHN, not examined). Jörgensen, 1912a: 131, 132; 1912b: 312.

Megachile( Chrysosarus) binota: Raw, 2002: 9; 2007: 31. Moure et al., 2007: 955. Durante et al., 2008: 432. Diagnosis. This species is distinguished by its black integument and vestiture, except for a small lateral patch of white hairs laterally on T2. The females can be distinguished from other species with extensively black vestiture as follows: from M. tetrazonaby its smaller size and lack of white tufts behind the pronotal lobe, from melanic individuals of M. jenseni by its narrow vertex, and from melanic individuals of M. ctenophora by the shorter vestiture and the sparser punctation of the scutum, the integument of which is polished between punctures.

Redescription. Female: Body length: 9.8-12.0 mm. Forewing length: 5.6-6.7 mm. Coloration. Integument black except: underside of flagellum and apex of mandible dark brown in some specimens. Wings subhyaline with light brownish tinge, and darker apices; veins and pterostigma dark brown. Pubescence. Head: entirely black. Mesosoma: entirely black. Disc of scutum with long hairs (1.0-1.5 x MOD), longer on scutellum (1.5-2.0 x MOD). Legs with black hairs, except black to brown on inner surface of tarsi. Metasoma: with black hairs, except T2 with white lateral patch occupying 1/ 3-1/4 of width of tergum; discs of T2-T4 with very short (0.3-0.8 x MOD) hairs, discs of T5-T6 with short and long hairs; T3-T5 with apical bands not dense (length of hairs 0.3-0.5 x MOD); scopa black. Structure. Inner margin of eyes slightly convergent below, proportion of upper to lower interocular distance 1.1; interantennal distance 1.45 x antennocular distance; distance between lateral ocellus and occipital margin 1.6-1.7 x MOD; proportions of scape, pedicel and first three flagellomeres 2.9:1.0:1.0:0.9:1.0; maximum width of gena 1.0-1.1 x maximum width of compound eye. Apical margin of clypeus denticulate; fourth mandibular tooth pointed. T6 slightly concave in profile, with rounded apex in dorsal view. Punctation. Clypeus with coarse, dense punctures, separated by shiny interspaces 0.1-0.5 x PD, supraclypeal area with shiny interspaces 0.2-0.3 x PD, some specimens with small impunctate area on center of supraclypeal area. Scutum and scutellum with punctures separated by shiny interspaces 0.2-0.5 x PD. Discs of T2-T5 shiny, punctures on disc of T2 small, separated by 1.0-3.0 x PD.

Distribution. Argentina, provinces of Chubut, Mendoza, Río Negro, and Santa Cruz.

Material examined. Argentina. Chubut: Comodoro Rivadavia, 1 F (MACN). Mendoza: Puente del Inca, 1 F (MACN); Puente del Inca, 2 F, 11-III-2010, Galvani (MACN); El Sosneado, 1 F, 22-I-2003, L. Compagnucci (MACN). Río Negr Negro: Ñorquinco, 5 km N Río Chico, 1 F, 21-I-2006, ex Nassauvia axillaris, D. Medan (MACN). Santa Cruz Cruz: Río Pinturas, Cueva Megachile (Dactylomegachile) ctenophora Holmberg Megachile ctenophora Holmberg, 1886: 144-146 (Lectotype male [Argentina, Buenos Aires, Tandil] MACN, examined, present designation). Dalla Torre, 1896: 427. Schrottky, 1903: 184. Friese, 1908: 63, 64, 68 (Tucumán). Jörgensen, 1909: 215, 224. Vachal, 1909: 229. Friese, 1911: 266. Jörgensen, 1912a: 128, 133, 135; 1912b: 311. Schrottky, 1913a: 247; 1909: 267 (Catamarca). Cockerell, 1917: 240 (Santa Fe). Megachile nigella Vachal, 1908: 223 (Holotype female, Argentina, Mendoza, XI, MNHN n° EY6319, examined). Jörgensen, 1912a: 131, 132; 1912b: 312. Cockerell, 1919: 219. New synonym.

Megachile ( Chrysosarus) ctenophora: Raw, 2002: 10; 2007: 34. Moure et al., 2007: 956. Durante et al., 2008: 432.

Megachile ( Chrysosarus) nigella: Raw, 2002: 11; 2007: 36. Moure et al., 2007: 958. Durante et al., 2008: 432.

Megachile ( Dactylomegachile) ctenophora: Durante & Cabrera, 2009: 57, fig. 12.

Diagnosis Diagnosis. This species is close to M. vagata, from which it is distinguished by the longer vestiture in both sexes. Females of M. ctenophora and M. vagata have an orange scopa and the integument of the scutum is tessellate between punctures, characters shared by M. jenseni, from which they are distinguished by the narrow vertex. Males of M. ctenophora differ from males of M. infima and M. jenseni in the pilose hypostomal area. Redescription. Female: Body length: 9.2-11.9 mm. Forewing length: 6.2-7.7 mm. Coloration. Integument black except: underside of flagellum and apex of mandible dark brown in some specimens. Wings subhyaline with light brownish tinge and darker apices; veins and pterostigma dark brown. Pubescence. Head: pale specimens with white hairs on paraocular areas and mid part of gena, and intermixed with black hairs on frons; dark specimens with pubescence entirely black.

Mesosoma: pale specimens with white patches behind pronotal lobe and above propodeal spiracle; hairs white intermixed with some black hairs on pronotal collar, on scutum and around scutellum; dark specimens with black hairs, except white patch behind pronotal lobe. Disc of scutum with long hairs (0.8-1.2 x MOD), longer on scutellum (1.2-2.0 x MOD). Legs with black hairs, except ferruginous on inner surface of tarsi. Metasoma: pale specimens with complete apical bands of long hairs on T1-T5 (0.4-0.6 x MOD on T1 and T2), hairs of bands white, plumose on T1-T2 and laterally on T3, black, mostly simple on middle of T3 and on T4-T5, and some simple golden hairs intermixed on T4-T5; discs of T2-T4 with very long, erect hairs (1.0-2.0 x MOD), white on T1-T2, intermixed with black hairs on T3-T4, and mostly black on T5. Dark specimens with white hairs reduced to short lateral bands on T1-T2. Scopa varying from ferruginous on S2-S5 to entirely black. Structure. Inner margin of eyes slightly convergent below, proportion of upper to lower interocular distance 1.1; interantennal distance 1.25x antennocular distance; distance between lateral ocellus and occipital margin 1.6-1.9 x MOD; proportions of scape, pedicel and first three flagellomeres 3.4:0.9:1.0:1.0:1.1; maximum width of gena 1.1 X maximum width of compound eye. Apical margin of clypeus denticulate; fourth mandibular tooth truncate, weakly incised. T6 slightly concave in profile, with rounded apex in dorsal view. Punctation. Clypeus with dense punctures, separated by shiny interspaces 0.1-0.2 x PD, supraclypeal area with interspaces 0.1-0.2 x PD, some specimens with small, impunctate, tessellate area on center of supraclypeal area. Scutum and scutellum with dense, homogeneous punctures, separated by tessellate interspaces 0.1-0.25 x PD. Discs of T2-T5 with tessellate interspaces; punctures on disc of T2 small, separated by 0.5-1.0 x PD.

Male: Body length: 8.7-10.6 mm. Forewing length: 5.9-7.3 mm. Coloration. Similar to that of female, except foreleg: under surface of femur and tibia, and entire tarsus ferruginous; underside of second tarsomere with black spot. Pubescence. Long, abundant, whitish hairs on clypeus, supraclypeal area, paraocular area, and gena; dark brown on remainder of head, intermixed with white hairs on vertex; hairs on hypostomal area varying from white to brown. Mesosoma: pale specimens with pubescence mostly white, except few intermixed, erect, long, dark brown hairs on scutum and black patch laterally on propodeum; dark specimens with dark brown hairs on mesopleuron below hypoepimeral area, on middle of metapleuron an on lateral side of propodeum. Foreleg: hairs on coxa white, on remainder of leg mostly orange and white, except tibia with short dark hairs on dorsal and outer surfaces; outer fringe of tarsus with orange hairs ventrally, covered with shorter white hairs dorsally. Middle and hind legs mostly with dark hairs, except middle tarsus with hairs paler. Metasoma: pale specimens on T1 with long, white hairs and poorly defined apical band; dark specimens on T1 with dark brown hairs. T2-T4 with black hairs on discs and whitish apical bands (varying from complete to medially interrupted). T5-T6 with black hairs. Structure. Lower margin of mandible forming triangular projection near middle. Hypostomal area pilose.

Maximum width of gena 1.2-1.3 x maximum width of compound eye. Anterior surface of forecoxa with sparse punctures bearing minute hairs, and group of 15-20 ferruginous bristles in front of coxal spine; spine of moderate length, 0.7 x MOD; lower outer margin of forefemur and tibia rounded. Anterior basitarsus flattened, proportion of lengths of basitarsus and second tarsomere along midline 1:0.7, basitarsus twice as long as its apical width. Carina of T6 with small median notch and laterally with 3-5 spiniform teeth; T6 with weak median depression above carina. Pregradular area of S5 with simple hairs laterally; postgradular area with medial area of stiff, basally thickened hairs, and remainder of area with simple hairs; separation area narrow, translucent (Fig. 1C). Lateral pregradular area of S6 with long hairs finely branched apically; central area bare medially and laterally with simple hairs directed mesally; apical lobes short, subtriangular, with a row of simple hairs running from one lobe to the other (Fig. 1C). Comments Comments. The citation of M. ctenophora for the province of Santa Fe (Cockerell, 1917) may be erroneous. The known distribution of the species is restricted to the south of the province of Buenos Aires, northern Patagonia and western Argentina. We know of no specimens from the mesic central parts of Argentina. The original description of Holmberg (1886) was based on several specimens from the town of Tandil, and from Cerro Claraz (today within the town of Tandil). The specimen selected as the lectotype bears a small triangle with no inscriptions (as is the case with many specimens in the Holmberg collection), a handwritten label " Megachile / ctenophora / Holmberg," a label "col. HOLMB.", and another label "SYNTYPUS". We added a lectotype label.

The specimens studied from Mendoza and northern Patagonia are smaller and darker than those of southern Buenos Aires. The type of M. nigella Vachal corresponds to the small, black morphotype. This species has been reared from trap nests in two localities (Bahía Blanca, province of Buenos Aires, and Villavicencio, province of Mendoza). Information on the nesting ecology of this species can be found in Dorado et al. (2011) and Dorado & Vázquez (2016).

Distribution. Argentina, provinces of Buenos Aires, Jujuy, Mendoza, Neuquén, Río Negro, and Salta. Material examined. Argentina. Buenos Air Aires es: Mar del Plata, 2 F, XII-2003, González Vaquero (MACN); Carmen de Patagones, 1 F, 30-XII-2007, T. Moyano, G. Moyano, A. Roig Alsina (MACN); Bahía Blanca, 1 F, 31-XI-2004, S. Villamil (MACN); Bahía Blanca, 2 F, 1 M, reared from trap-nest, emerged 22-23-II-2016, S.C. Villamil (MACN); 1 F, 2 M, reared from trap-nest, emerged 2-4-I-2016, S.C. Villamil (MACN); Bahia Blanca, 1 M, 22-XII-2008, H.J. Marrero (FAUBA); Tandil, Ea. Lonacepin, 1 F, 27-XII-1934 (MLP); Monte Hermoso, 1 M, 19-XII-1974 (MLP). Jujuy Jujuy: Tumbayá, 1 M, 20-XI-1992, A. Roig A. (MACN); Huacalera, 17 km N Tilcara, 2800m, 2 M, 6-I-1982, D. Brothers (SEMC). Mendoza: Cacheuta, 2 F, 3 M (MACN); Uspallata, 1 F, II-1973, A. Roig A. (MACN); Potrerillos, 1 F, 24-III-1979, A. Roig A. (MACN); Mina Aída, 1 F, A. Stevenin (MACN); Villavicencio, 14 F, 7 M, reared from traps, D. Vázquez, N. Chacoff & J. Dorado (MACN); Uspallata, 4 M and 1 F, 16-XII-1954, A. Ogloblin (MLP); 1 M, 3-I-1908, Jörgensen (MLP); 1 F, 17-XI-1907, Jörgensen (MLP); 2 F, 20-III-1908, Jörgensen (MLP); Challao, Cº Bodega, 1 M, III-1997, Roig & Debandi (IADIZA); Poterillos, Aº Tres Saltos, 1 F, 19-XII-2002, G. Debandi (IADIZA); Godoy Cruz, Puesto Chambón, 1 F, 25-II-1995, G. Debandi (IADIZA). Neuquén: Rinconada, 2 F, 25-I-1965, A. Giai (MACN); Chapelcó, 1 F, I-1963, A. Giai (MACN); Quequemtreu, 3 F, 3-II-1963, A. Giai (SEMC); Collón Curá, 1F, 1 M, 25-I-1963, A. Giai (SEMC); San Martín de los Andes, 2 F, I-1953, Schajovskoi (MLP); San Martín de los Andes, 3 F, II-1954, Schajovskoi (MLP); San Martín de los Andes, 1 F, III-1954, Schajovskoi (MLP); San Martín de los Andes, 4 F, 3-III-1953, A. Ogloblin (MLP); Junín de los Andes, 1 F, 17-XI-1965, Schajovskoi (MLP); Río Aluminé, 2 F, 29-II-1964, 7-XII-1964, Schajovskoi (MLP). Río Negr Negro: Paso Flores, 4 F, II-1963, A. Giai (SEMC); Paso Córdoba, 8 km SW Gral. Roca, 1 M, 6-7-XI-1997, C. & M. Vardy (NHMUK); Old INTA station, ca. 13 km W Gral. Roca, 1F, 9-XI-1997, C. & M. Vardy (NHMUK); Paso Flores, 2 F, 13-II-1956, S. Schajovskoi (MLP); Comallo, 2 F, I-1943, Marti (MLP). Salta: Tastil, 3200 m a.s.l., 1 M, 12-I-1994, M.F. Trucco Alemán (MACN). BOLIVIA. Villazón, 2 F, 1 M, 7-I-1988, L. Moffatt (MACN).

Megachile ( Dactylomegachile) infima Vachal

Megachile infima Vachal, 1908: 238-239 (Syntypes female and male, Mendoza, XII, MNHN, examined). Vachal, 1909: 13. Jörgensen, 1912a: 131; 1912b: 312. Schrottky, 1920: 210. Cockerell, 1927: 395. Megachile simillima: Friese, 1906:

(misidentification, specimens from Mendoza, Argentina). Friese, 1908: 65 (idem) . Jensen-Haarup, 1908: 105 (idem) . Jörgensen, 1909: 214 (idem) . Megachile parsonsiae Jörgensen, 1912a: 128; 1912b: 311 (Nomen nudum).

Megachile parsonsiae Schrottky, 1913b: 197 (Syntypes female and male, Misiones, Argentina, Asunción and V. Encarnación, Paraguay, not examined). Schrottky, 1913a: 247. Cockerell, 1914: 428; 1917: 240; 1926: 216. Ramos et al., 2015: 357 (Two syntypes, male and female, from V. Encarnación, Paraguay preserved at Museu de Zoologia, São Paulo). New synonym. Megachile riojanensis Mitchell, 1930: 302 (Holotype female, La Rioja, Argentina, MCZ nº 6208, examined). New synonymNew synonym.

Megachile (Dactylomegachile ) parsonsiae : Mitchell, 1943: 670. Silveira Megachile (Chrysosarus) parsonsiae: Michener, 2000: 553. Raw, 2007: 37. Moure et al., 2007: 958. Megachile (Chrysosarus) infima : Raw, 2002: 10; 2007: 35. Moure et al., 2007: 957. Megachile (Chrysosarus ) riojanensis : Raw, 2002: 11; 2007: 38. Moure et al., 2007: 959. Megachile (Dactylomegachile) infima: Durante & Cabrera, 2009: 57. Megachile (Dactylomegachile ) riojanensis : Durante & Cabrera, 2009: 57. Diagnosis Diagnosis. This species is the smallest of the subgenus. The females are recognized by the presence of sternal pilose lateral bands below the scopa. The males are distinguished by the glabrous hypostomal area, a feature shared with M. jenseni , from which it is distinguished by the narrower vertex, and the lower margin of the mandible with an angle near middle (on basal third in M. jenseni ).

Redescription. Female: Body length: 6.7-9.4 mm. Forewing length: 5.0-6.5 mm. Coloration . Integument black except: dark brown on underside of flagellum, tegula, legs, and tibial spurs; apex of mandible and claws dark ferruginous (although claws dark brown apically). Wings hyaline to weakly infuscate, costal margin of forewing with strongly infuscate band which on marginal cell occupies over half of cell; veins and pterostigma dark brown. Pubescence . Head: white on paraocular area, lateral margin of clypeus, gena and underside of head; white with intermixed black hairs on rest of clypeus, supraclipeal area and frons; vertex with erect, long black hairs and decumbent, short, brownish hairs. Mesosoma: dense, white patches on dorsolateral angle of pronotal collar, pronotal lobe, on anterior end of tegula, on scutum anteriorly to axilla, and above propodeal spiracle; hairs on upper half of meso and metapleura varying from white to entirely black; intermixed white and black hairs on disc of scutum and scutellum; remainder of mesosoma with sparse white hairs; hairs on disc of scutum short (0.3-0.4 x MOD) with sparse, intermixed longer hairs (0.9-1.1 x MOD hairs on scutellum long (1.5-2.0 x MOD). Legs with white hairs, except yellowish to ferruginous on inner surface of tarsi. Metasoma: with complete apical bands of short, plumose hairs on T1-T5 (0.5-0.6 x MOD on T1 and T2), usually basal bands whitish and apical ones yellow; discs of T2-T4 with very short (0.3-0.4 x MOD) pale hairs, discs of T5-T6 with pale hairs intermixed with longer black ones; S2-S5 with incomplete apical bands of dense yellow hairs occupying lateral 0.16 (on S2) to 0.30 (on S5) of width of sternum; scopa yellowish; S6 with yellowish hairs basally and black hairs apically. Structure . Inner margin of eyes slightly convergent below, proportion of upper to lower interocular distance 1.15; interantennal distance 1.4-1.5x antennocular distance; distance between lateral ocellus and occipital margin 1.5-1.6 x DOM; proportions of scape, pedicel and first three flagellomeres 3.3:1.0:1.0:1.0:1.1; maximum width of gena 0.80 x maximum width of compound eye. Apical margin of clypeus denticulate; fourth mandibular tooth truncate, incised. T6 slightly concave in profile, with rounded apex in dorsal view. Punctation . Clypeus with dense punctures, separated by shiny interspaces 0.10-0.25x PD, supraclypeal area with tessellate interspaces 0.1-0.3x PD, some specimens with small impunctate area on center of supraclypeal area. Scutum and scutellum with dense punctures, separated by shiny interspaces 0.10-0.25x PD. Integument of T2-T5 shiny on discs, weakly tessellate on pregradular areas; punctures on disc of T2 small, separated by 0.8-1.0x PD.

Male: Body length: 5.3-7.5 mm. Forewing length: 4.7-5.3 mm. Coloration . Similar to that of female, except foreleg: under surface of femur and tibia, and entire tarsus yellowish to ferruginous; underside of second tarsomere with black spot. Pubescence. Long, abundant, yellowish hairs on clypeus, supraclypeal and paraocular area, brown on vertex and disc of scutum and scutellum, remainder of head and mesosoma, and legs with whitish hairs; outer fringe of anterior basitarsus and first two tarsomeres with hairs white, short: on basitarsus as long as 1.0-1.5 x apical width of basitarsus. T1-T5 with complete apical bands of short, plumose, whitish to yellowish hairs; disc of T2-T5 with brown hairs, paler on basal terga and nearly black on T5-T6; S2-S4 with complete apical white fringes. Structure . Lower margin of mandible forming triangular projection near middle. Hypostomal area flattened, forming large, glabrous, polished area. Maximum width of gena 0.9-1.0 x maximum width of compound eye. Anterior surface of forecoxa with sparse punctures bearing minute hairs, and group of 4-5 ferruginous bristles in front of coxal spines; spines of moderate length, 1.0 x MOD; lower outer margin of forefemur sharply angled, of foretibia carinate. Anterior basitarsus weakly modified, proportion of lengths of basitarsus and second tarsomere along midline 1:0.80, basitarsus twice as long as its apical width. Carina of T6 with small median notch and laterally with 4-5 spiniform teeth; T6 without anterior depression. Pregradular area of S5 with simple hairs laterally; postgradular area with medial area of stiff, basally thickened hairs, and remainder of area with simple hairs; separation area narrow, translucent (Fig. 1A). Lateral pregradular area of S6 with long hairs finely branched apically; central area bare medially and laterally with short, simple hairs directed mesally; apical lobes glabrous, short, subtriangular (Fig. 1A).

Comments Comments. Specimens in collections have usually been identified as M. infima. The species has a broad distribution, from Mendoza in Argentina (Jörgensen, 1912a, 1912b) to the state of São Paulo in Brazil (Silveira et al., 2002). The name M. infima has only been cited in lists or catalogs after its description, although Schrottky (1920) recognized that his M. parsonsiae and M. infima may belong to a “ collective species”. The study of the type of M. infima shows that it corresponds to the same species. This species has been reared from trap nests in the locality of Berisso, province of Buenos Aires.

Distribution Distribution. Argentina, provinces of Buenos Aires, Catamarca, Chaco, Córdoba, Corrientes, Entre Ríos, Formosa, Jujuy, La Rioja, Mendoza, Misiones, Salta, San Juan, San Luis, Santa Fe, Santiago del Estero, and Tucumán. Material examined examined. Argentina. Buenos Air Aires es: 1 F, 17-XII-1908, A. Zotta (MACN); Buenos Aires, 1 F, 4-IV-1904, J. Brèthes (MACN); Ciudad de Buenos Aires, Reserva Costanera Sur, 1 F, 2 M, 20-I-2012, Compagnucci, Galvani & González Vaquero (MACN); Jardín Botánico Facultad de Agronomía, CABA, 1 F, 11-XI-2009, N. Mazzeo & J.P. Torretta (FAUBA); Berisso, 5 M, 2 F, 23/26-XII-2010 (reared from trap nests), L. Álvarez (MLP); Canal San Fernando, 2 M, 1 F, 25-XI-1945 (MLP). Catamar Catamarca ca: Manantiales, 1 F, 15-30-I-1960, I. Apóstol (MACN); Valle Viejo, San Isidro, El Bañado, 1 F, 17-IV-1936 (MLP); Las Viñas, 1 M, 9-XI-1942, A. Ogloblin (MLP); Andalgalá, 1 M, 19-XI-1944, A. Ogloblin (MLP); 1 M, C.S. Reed (MLP). Chaco Chaco: Roque Sáenz Peña, 1 M, 1930, Ohnmeiser (MACN); P.N. Chaco, 1 F, 12-13-XI-2007, L. Compagnucci (MACN); Capitán Solari, P.N. Chaco, 1 F, 5-V-2008, A. Taylor & N. Veiga (MACN); Resistencia, 1 M, 17-XI-1945, A. Ogloblin (MLP); Roque Sáenz Peña, 1 F, 11-XI-2004, J.P. Torretta & N. Montaldo (FAUBA). Cór Córdoba doba: San Marcos Sierras, 1 M, 7-15-I-2005, L. Compagnucci (MACN); Huinca Renancó, 1 F, 14-II-1977, sobre girasol (MLP). Corrientes Corrientes: Santa Teresa, Parque Nacional Mburucuyá, 2 F, 5-17-X-2009, N. Veiga (MACN). Entr Entre Ríos Ríos: Palmar de Colón, 1 F, 10-XI-1995, Di Iorio (MACN); Pronunciamiento, 1 M, I-1961, M. Zelich (MLP). For Formosa mosa: El Colorado, INTA, 1 M, 23-X-2010, Roig A. et al., ex Prosopis sp. (MACN); Laguna Yema, 1 F, 5 M, L. Damer (MACN); San Francisco de Laishi, Reserva El Bagual, 1 F, 7-I-2014, J.P. Torretta (FAUBA). Jujuy Jujuy: 1 M, (MACN); Yuto, 1 M, 10-IV-1911, Jörgensen (MLP). La Rioja Rioja: 48 M, 15 F, E. Giacomelli col., cat. nº 11765 (MACN); 2 M, 2 F, Gemigani col., cat. nº 11095 (MACN); Malanzán, 1 M, II-1923, M. Gómez (MACN); Iliar, 1 F, V-1932, M. Gómez (MACN); 2 M, C.S. Reed (MLP). Mendoza Mendoza: ciudad Mendoza, 1 F, II-1973, A. Roig A. (MACN); Mendoza,1 F,17-II-1906, P. Jörgensen (MLP); Mendoza, 1 M, 12-I-1907, P. Jörgensen (MLP); Mendoza, 1 F, 5-III-1910, P. Jörgensen (MLP); 2 F, 3 M, C.S. Reed (MLP); 1 M, X-1920, C.S. Reed (MLP); Chacras de Coria, 2 M (MLP); Pedriel, Depto. Maipú, 1 M, G. Debandi (IADIZA). Misiones Misiones: Posadas, 2 M (MACN); Campo Viera, 1 F, XII-1957 (SEMC); Loreto, 1 M, A. Ogloblin (MLP); Bompland, 1 F, 14-II-1911, Jörgensen (MLP); 1 M, 11-I-1911, Jörgensen (MLP). Salta: Puesto Zapallar, ca. San Patricio (23º 51' 50'' S – 62º 34' 34'' W), 1 F, J. Meriggi (MACN); Coronel Moldes, 1 M, 28-XII-1992, A. Roig A. & L. Horovitz (MACN); Rosario de Lerma, XII-1992, A. Roig A. & L. Horovitz (MACN); Saucelito, 1 M, 1-XII-1957, A. Ogloblin (MLP). San San Juan Juan: Ciudad de San Juan, 1 M, 21-XII-1920, F.T. Amal (MACN); Pocito, Rinconada, 1 F, 1 M, 26-I-1937 (MLP); 1 M, C.S. Reed (MLP). San San Luis Luis: Suyuque Viejo, 1 M, 17-I-1982, A. Roig A. (MACN); Parque Nacional Sierra Las Quijadas, 1 F, 4-5-I-2003, Compagnucci (MACN). Santa Fe: Esperanza, 1 F, 9-II-2005, M. Dalmazzo (MACN); Guadalupe, 5 M, 8-I-1945, A. Ogloblin (MLP). Santiago del Ester Estero: 1 F, 5 M, X-1929, M. Gómez (MACN); Fernández, 1 F, II-1957 (SEMC); Termas de Río Hondo, 6 M, 4 F, 17-XI-1951, A. Ogloblin (MLP). Tucumán ucumán: Tafí Viejo, 1 M, II-1914, Girard (MACN); 11 km N Cadillal, 1 M, 7-XI-1993, A. Roig A. (MACN); 6 km W Tapia, 1 F, 20-XI-1993, A. Roig A. (MACN); Tucumán, 1 F, Arnau (SEMC).

Megachile ( Dactylomegachile) jenseni Friese

Megachile jenseni Friese, 1906: 95 (Type female, Mendoza, Januar, ZMB, not examined). Friese, 1908: 63, 65, 67, 68. Jensen-Haarup, 1908: 105. Vachal, 1909: 12. Jörgensen, 1909: 214. Strand, 1910: 535. Jörgensen, 1912a: 127, 132, 133, 135; 1912b: 310. Friese, 1912: 364. Schrottky, 1913a: 247. Cockerell, 1914: 427. Schrottky, 1920: 206. Hedicke, 1933: 43. Megachile (Dactylomegachile) jenseni: Mitchell, 1943: 671. Durante & Cabrera, 2009: 57, figs. 4, 6. Megachile (Chrysosarus) jenseni: Raw, 2002: 11; 2007: 36. Moure et al., 2007: 956. Durante et al., 2008: 432.

Diagnosis Diagnosis. This species is distinguished by a broad vertex. Females are characterized by an orange scopa, and males by the concave lower margin of the mandible ending in an angle near the basal third, and by the preapical carina of T6 denticulate, without median emargination.

Redescription. Female: Body length: 11.0-12.8 mm. Forewing length: 6.9-7.6 mm. Coloration. Integument black except: underside of flagellum and apex of mandible dark brown in some specimens. Wings weakly infuscate with darker apices; veins and pterostigma brown. Pubescence. Head: pale specimens with white hairs on paraocular areas and mid part of gena and intermixed with black hairs on frons; dark specimens with pubescence entirely black. Mesosoma: pale specimens with white patches behind pronotal lobe and above propodeal spiracle; white hairs intermixed with some black hairs on pronotal collar, on scutum, around scutellum and on posterior surface of propodeum; dark specimens with black hairs, except white patch behind pronotal lobe. Disc of scutum with long hairs (0.9-1.1 x MOD), longer on scutellum (1.8-2.5 x MOD). Legs with black hairs, except ferruginous on inner surface of tarsi. Metasoma: pale specimens with complete apical bands of white, plumose hairs on T1-T5 (0.5-1.5 x MOD on T1 and T2); discs of T2-T4 with long, erect hairs (0.3-0-5 x MOD); discs of T1-T5 with black hairs and some intermixed white hairs; T6 with black hairs. Dark specimens with white hairs reduced to short lateral bands on T1-T2. Scopa varying from ferruginous on S2-S6 to entirely black. Structure . Inner margin of eyes slightly convergent below, proportion of upper to lower interocular distance 1.11; interantennal distance 1.3 x antennocular distance; distance between lateral ocellus and occipital margin 2.1-2.3 x diameter of ocellus; proportions of scape, pedicel and first three flagellomeres 3.2:0.9:1.0:1.0:1.0; maximum width of gena 1.25 x maximum width of compound eye. Apical margin of clypeus with median narrow emargination bearing three denticles, irregular laterally; fourth mandibular tooth truncate, weakly incised. T6 slightly concave in profile, with rounded apex in dorsal view. Punctation . Clypeus with dense punctures, separated by shiny interspaces 0.10-0.20 x PD, supraclypeal area with interspaces 0.2-0.2 x PD. Scutum and scutellum with dense, homogeneous punctures, separated by tessellate interspaces 0.10-0.40 x PD. Discs of T2-T5 tessellate; punctures on disc of T2 separated by 0.2-1.0 x PD.

Male: Body length: 10.2-11.5 mm. Forewing length: 6.0-6.4 mm. Coloration . Similar to that of female, except foreleg: under surface of femur and tibia ferruginous, and entire tarsus yellowish; underside of second tarsomere with black spot. Pubescence . Long, abundant, yellowish hairs on clypeus, supraclypeal and paraocular areas; hairs dark brown on remainder of head except white on gena and long white hairs surrounding glabrous space of hypostomal area. Mesosoma entirely with white hairs. Foreleg: hairs on coxa and trochanter white, on remainder of leg mostly orange and white, except tibia with short dark hairs on dorsal and outer surfaces; outer fringe of tarsus with orange hairs ventrally, which are covered with shorter white hairs dorsally. Middle and hind legs mostly with dark hairs, except middle tarsus with hairs paler. Metasoma: T1-T2 with long, white hairs on discs and white apical bands; T3-T4 with dark hairs on discs and yellowish apical bands (varying from complete to medially interrupted); T5-T6 with black hairs. Structure . Lower margin of mandible concave, forming triangular projection near basal third. Hypostomal area flattened forming large, glabrous, polished area. Gena wider than compound eye (1.1:1.0). Anterior surface of forecoxa with sparse punctures bearing minute hairs, and group of 10-15 ferruginous bristles in front of coxal spine; spines of moderate length, 1.0 x MOD; lower outer margin of forefemur rounded, of tibia carinate. Anterior basitarsus flattened, proportion of lengths of basitarsus and second tarsomere along midline 1:0.80, basitarsus 1.60 as long as its apical width. Carina of T6 without median notch, with 8-12 spiniform teeth; T6 with weak median depression above carina. Pregradular area of S5 with simple hairs laterally; postgradular area with medial area of stiff, basally thickened hairs, and remainder of area with simple hairs, without separation area (Fig. 1B). Lateral pregradular area of S6 with long hairs finely branched apically; central area with simple hairs directed mesally; apical lobes glabrous, short, apically rounded, directed laterally (Fig. 1B). Comments Comments. This species varies in the color of the pubescence. In the above description, only the palest and the darkest specimens are described, but all intermediates occur. This species has been reared from trap nests in the localities of Pila and Carlos Casares, province of Buenos Aires.

Distribution Distribution. Argentina, provinces of Buenos Aires, Chubut, La Rioja, Mendoza, Neuquén, Río Negro, and San Juan.

Material examined examined. Argentina. Buenos Air Aires es: Pila, Ea. Las Chilcas, 10 F and 4 M (reared from trap-nests), 17-VIII-2011/15-X-2011 (emergence dates), J.P. Torretta (MACN); C. Casares, Ea. San Claudio, 2 F and 3 M (reared from trap-nests), J.P. Torretta (MACN); C. Casares, Ea. San Claudio,1 F, 5-XII-2008, ex Raphanus sativus, J.P. Torretta (MACN); C. Casares, Ea. San Claudio, 15 F and 15 M, (reared from trap-nests), XII-2015/III-2016, J.P. Torretta (FAUBA) ; Pila, Ea. Las Chilcas, 20 F and 20 M, (reared from trap-nests), XII-2011/II-2012, J.P. Torretta (FAUBA); H. Ascasubi, 3 M, 1 F, 10-I-1975, Teson & Dagoberto (MLP); Felipe Solá, 2 M, 13-I and 30-I-1946, A. Ogloblin (MLP); San Fernando, 2 F, 15-XII-1946 (MLP); Berisso, 2 F (nest # 29), 7-XI-2012 and 9-XI-2012, L. Álvarez (MLP); Berisso, 2M, 2 F (nest # 27), 6-XI-2012, L. Álvarez (MLP). Chubut Chubut: Trelew, 1 M, 20-I-1961 (MLP); 1 F (MACN). La Rioja Rioja: Jagüel, 1 M, 22-I-2006, L. Compagnucci (MACN); La Rioja, 1 F, C.S. Reed (MLP). Mendoza Mendoza: Uspallata, 1 F, 9-I-2003, Compagnucci (MACN); Uspallata, 1 M, 16-XII-1954, A. Ogloblin (MLP); 1 M, 1 F, C.S. Reed (MLP); 6 F, 7-XI-1906, 10-XI-1906, 10-XII-1906, 17-XI-1907, 10-XII-1907, 20-III-1907, P. Jörgensen (MLP); 2 M, 17-XI-1907, 11-XI-1908, P. Jörgensen (MLP). Neuquén Neuquén: Quequemtreu, 1 F, 3-II-1963, Giai (SEMC). Río Negr Negro: Paso Flores, 2 F, III-1963 (MACN); Paso Flores, 1M, III-1963 (SEMC); INTA station, ca. 18 km W Gral. Roca, 1F, 27-II-1998, YPT, C. & M. Vardy (NHMUK); Río Colorado, 1 M, II-1943 (MLP). San Juan Juan: Pocito, Va. Aberastain, 1 M, 22-1-1964, Torres-Ferreyra (MLP); 3 F, San Juan, X-1941, Ch. Molinari (MLP).

Megachile (Dactylomegachile) leucografa Friese Megachile leucografa Friese, 1908: 63, 67 (Lectotype female, Argentina, Mendoza, 18-XII-1906, Jensen, "Lectotypus, Fritz", ZMHU, examined, pr present esent designation designation). Jörgensen, 1909: 215. Schrottky, 1920: 203.

Megachile trochantina Vachal, 1909: 14 (Lectotype male, Argentina, Mendoza, 20-I-1906, Rolle H., Berlim W., MNHN, examined, designated by Durante, 1994). Jörgensen, 1912a: 132, 135; 1912b: 312. New synonym. Megachile leucographa: Jörgensen, 1912a: 125, 126, 128, 133, 135; 1912b: 309, 311. Schrottky, 1913a: 247. Durante et al., 2008: 433.

Megachile perspicua Mitchell, 1930: 289-290, pl. XIV (Holotype female, Argentina, Córdoba, Davis, MCZ n°16203, examined). New synonym Chrysosarus ( Dactylomegachile) trochantina: Durante, 1994: 41-44, Figs. 1-9 (Lectotype designation). Megachile ( Chrysosarus) trochantina: Raw, 2002: 12; 2007: 38. Moure et al., 2007: 959. Durante et al., 2008: 432.

Megachile ( Chrysosarus) perspicua: Raw, 2002: 11; 2007: 37. Moure et al., 2007: 958. Durante et al., 2008: 432.

Megachile ( Chrysosarus) leucographa: Moure et al., 2007: 957.

Megachile ( Dactylomegachile) leucographa: Durante & Cabrera, 2009: 57, figs. 8, 14.

Diagnosis Diagnosis. Females of this species are readily distinguished by the pointed fourth tooth of the mandible, the apical margin of the clypeus with a median smooth emargination, and by a white scutoscutellar band of hairs. Males are distinguished by the preapical carina of T6 emarginate, without spines, and by the basal tuft of yellowish hairs on the lower margin of the mandible.

Redescription. Female: Body length: 8.9-11.4 mm. Forewing length: 5.9-7.1 mm. Coloration. Integument black except: underside of flagellum, tegula, legs, and tibial spurs dark brown (some specimens darker), apex of mandible and claws dark ferruginous (although claws dark brown apically). Wings subhyaline with a light brownish tinge, with darker apices; veins and pterostigma brown. Pubescence. Head: white hairs on paraocular areas and gena, and intermixed white and black hairs on frons. Mesosoma: dense, white patch on dorsolateral angle of pronotal collar continued to pronotal lobe and anterior part of tegula; white, short, plumose, hairs forming a dense patch on lateral margin of scutum and a band on scuto-scutellar suture; band of white hairs on posterior margin of scutellum and metanotum; white longer, sparse, hairs on mid part of pronotum, anterior part of scutum, upper part of metapleura, and lateral and posterior side of propodeum. Disc of scutum with short (0.2-0.6 x MOD), black hairs, longer on scutellum (0.9-1.7 x MOD). In some specimens with white patch in front of mid coxa.

Coxae, trochanters, and femora with black hairs, except front femur with some intermixed white hairs in some specimens; outer surface of tibiae and tarsi with white hairs; and inner surface of tarsi with ferruginous hairs. Metasoma: with complete apical bands of short, plumose hairs on T1-T5 (0.8-1.2 x MOD on T1 and T2), usually basal bands whitish and apical ones yellowish; disc of T2-T4 with short (0.2-0.6 x MOD) brownish hairs; T6 with pale, decumbent hairs intermixed with longer brownish ones; scopa whitish, except S6 with black hairs. Structure. Inner margin of eyes slightly convergent below, proportion of upper to lower interocular distance 1.1; interantennal distance 1.3x antennocular distance; distance between lateral ocellus and occipital margin 2.2-2.6 x MOD; proportions of scape, pedicel and first three flagellomeres 3.8:1.0:1.0:1.0:1.1; maximum width of gena 1.1 x maximum width of compound eye. Apical margin of clypeus with median smooth emargination; fourth mandibular tooth pointed. T6 slightly concave in profile, with rounded apex in dorsal view. Punctation. Clypeus with punctures separated by shiny interspaces 0.1-0.2 x PD, supraclypeal area with tessellate interspaces 0.2-0.4 x PD, and with impunctate, tessellate area on center of supraclypeal area. Scutum and scutellum with dense punctures, separated by tessellate interspaces 0.1-0.5 x PD. Discs of T2-T5 weakly tessellate; punctures on disc of T2 separated by 0.4-1.0 x PD.

Male: Body length: 9.0-11.9 mm. Forewing length: 5.5-7.7 mm. Coloration. Similar to that of female, except foreleg: under surface of femur and tibia, and entire tarsus yellowish to ferruginous; underside of second tarsomere with black spot. Pubescence. Hairs long, abundant, white on clypeus, supraclypeal and paraocular areas, sparser, white to brownish on vertex, yellowish on gena and hypostomal area, white on remainder of head. Mesosoma with whitish hairs; scutoscutellar band conspicuous. Mandible on lower surface with conspicuous basal tuft of dense yellow hairs. Foreleg: hairs on coxa and trochanter white, on femur orange, on tibia whitish; outer fringe of tarsus with yellowish hairs ventrally (as long as 2.0-2.3 x apical width of basitarsus), covered with shorter white hairs dorsally. Middle and hind legs with white hairs, long on middle (2.0-3.0 x MOD), and hind (1.8-2.5 x MOD) basitarsi. T1-T4 with complete apical bands of short, plumose, whitish to yellowish hairs; few specimens also with band on T5; T1-T2 with long white hairs on discs; discs of T3-T4 with intermixed white and brown hairs; T5-T6 with hairs nearly black on T5- T6. S2-S4 with scattered short hairs on discs and lateral, apical white fringes. Structure. Lower margin of mandible forming angle near middle. Gena wider than compound eye (1.0:0.85). Anterior surface of forecoxa with sparse punctures bearing minute hairs, and group of 10-12 ferruginous bristles; spine 1.0 x MOD; lower outer margin of forefemur carinate, of foretibia rounded. Anterior basitarsus wide, flattened, proportion of lengths of basitarsus and second tarsomere along midline 1.0:0.9, basitarsus 1.5 as long as its apical width. Carina of T6 with median notch and undulate laterally; T6 with anterior depression. Pregradular area of S5 with simple hairs laterally; postgradular area with glabrous, translucent area of separation occupying basal half, and apical half with simple hairs. Lateral pregradular area of S6 with long hairs finely branched apically, margined laterally by short hairs; central area of sternum with short, simple hairs; apical lobes glabrous, broad, truncate, subcuadrangular. Comments Comments. Figures of the hidden sterna and genitalia of the male were presented by Durante (1994) under the name M. trochantina. This species has been reared from trap nests in two localities (Pila, province of Buenos Aires, and Villavicencio, province of Mendoza). These specimens allowed the correct association of the sexes. Information on the nesting ecology of this species can be found in Dorado & Vázquez (2016). The female lectotype of M. leucografa was labelled as such by M. Fritz, but he never published this designation. This specimen is designated as the lectotype herein. The holotype of M. perspicua agrees in all details with M. leucografa.

Distribution Distribution. Argentina, provinces of Buenos Aires, Catamarca, Córdoba, La Pampa, La Rioja, Mendoza, Neuquén, Salta, San Juan, San Luis, Santiago del Estero and Tucumán.

Material examined examined. Argentina. Buenos Air Aires es: 1 M, 20-II-1909 (MLP); Bella Vista, 2 M, 20-XII-1958 (MLP); Canal San Fernando, 1 F, 24-XII-1951, A. Ogloblin (MLP); Pila, Ea. Las Chilcas, 10 F and 4 M (reared from trap-nests), 17-VIII-2011/15-X-2011 (emergence dates), J.P. Torretta (MACN); C. Casares, Ea. San Claudio, 2 F and 3 M (reared from trap-nests), J.P. Torretta (MACN); C. Casares, Ea. San Claudio,1 F, 5-XII-2008, ex Raphanus sativus, J.P. Torretta (MACN). Catamar Catamarca ca: 1M, 27-XI-1941 (MLP); Andalgalá, 1M, 19-XI-1944, A. Ogloblin (MLP); San Antonio Paz, 10-XII, 1952, (MLP); Catamarca, 2 F, 22-XI-1944, A. Ogloblin (MLP); Campo El Arenal, 1 M, 15-XI-1993, A. Roig A. (MACN); Hualfín, 3 F, 30-I-2010, J.P. Torretta, ex Larrea nitida (MACN); San Fernando, 50 km N Belén, 3 M, 1 F, 4-XI-1989, L. Moffatt (MACN); Chumbicha, 1 F, 22-XI-1944, A. Ogloblin (MLP). Cór Córdoba doba: Serrezuela, 1 M, 1 F 26-XI-1944, A. Ogloblin (MLP); Quilino, 2 M, 8-XI-1942, 3-XII-1942, A. Ogloblin (MLP); Córdoba, 1 M, 26-XI-1944, A. Ogloblin (MLP); Chancaní, 10 M, 10 F, X-1991, Genise, Farina & Hazeldine (MACN); Villa Dolores, 8 M, 23-X-1989, J. Genise, ex Prosopis sp. (MACN); El Sauce, 1 M, 16-X-1970, G. Williner (MACN); Ciudad de Córdoba, 1 M, 27-XI-1927, M. Gómez, cat. nº 21516 (MACN). La Pampa Pampa: Toay, Ea. Anquilóo, 1 M, 11-XII-2010, Torretta (MACN); Santa Isabel, 3 M, 14-I-2007, Compagnucci, Martínez, Ojanguren (MACN). La Rioja Rioja: 25 Km N Chepes, La Puerta, 1 F, 11-X-1997, S. Roig (IADIZA); Cuesta de Miranda, Piedra Pintada, 2 F, 12-X-1997, S. Roig (IADIZA); 10 Km S Vinchina, 3 F, 13-X-1997, S. Roig (IADIZA); 15 Km W Chamical, 1 F, 21-X-1997, S. Roig (IADIZA); Iliar, 11 F, 2 M, 30-X-1928, M. Gomez (SEMC); Iliar; 1 M, 4 F, V-1932, M. Gomez (SEMC); Iliar, 2 F, 3 M, I-1935, M. Gomez (SEMC); Iliar, 1 F, II-1934, M. Gomez (SEMC); Estación Amado, 3 F, X-1934, M. Gomez (SEMC); Anillaco, 12 F, 1-6-XI-2011, Roig A., González V. & Compagnucci (MACN); Anillaco, 1 F, 1-6-XI-2011, Roig A., González V. & Compagnucci, ex Prosopis sp. (MACN); 3 Km SE Pinchas, 1 F, 4-5-XI-2011, Roig A., González V. & Compagnucci, ex Cercidium praecox (MACN); 3 Km SE Pinchas, 1 M, 4-5-XI-2011, Roig A., González V. & Compagnucci, ex Capparis atamisquea (MACN); Sanagasta, subida a Pampa de la Viuda, 8 F, 4-XI-2011, Roig A., González V. & Compagnucci, ex Larrea divaricata(MACN); Chilecito, Samaihuasi, 1 F, 2 M, 23-XI-1927, M. Gómez, cat. nº 21491-21492 (MACN); Nonogasta, 2 F, XI-1927, M. Gómez, cat. nº 21609 (MACN); Estación Amado, 12-I-1922, M.P. Gómez (MACN); Guayapa, Patquía, 1 M, 12-X-1965, E. Maury (MACN); Guayapa, Patquía, 1 M, 16-XI-1961, L. Yivoff (MACN); Iliar, 1 M, V-1932, M. Gómez (MACN); Patquía, 1 M, 3-X-1954, Pastrana (MLP); Sañogasta 1 M, 24-II-1939, Biraben-Scott (MLP); La Rioja, 1 M, 26-XI-1941 (MLP); La Sébila, 10 F, 24-XI-1944, A. Ogloblin (MLP). Mendoza Mendoza: Godoy Cruz, Pto. Chambón, 8 F, 1/5-XII-1995, G. Debandi (IADIZA); Lavalle, Reserva Telteca, 3 F, 18/25-X-1997, S. Roig (IADIZA); Santa Rosa, Reserva Ñacuñan, 6 F, XI/ XII-1998, S. Roig (IADIZA); Santa Rosa, Reserva Ñacuñan, 1 F, 25-XI-2000, G. Debandi, ex Larrea divaricata (IADIZA); 2 M and 1 F, 17/20-II-1906, P. Jörgensen (MLP); 1 M, 2-II-1907, Jörgensen (MLP); 1 M, 1 F, 20-II-1907 (reared from trap-nests), P. Jörgensen (MLP); 2 M, C.S. Reed (MLP); Monte Comán, 1 M, 24-XI-1944, Daguerre (MLP); 10 km W Carrizal, 1 M, 6-I-1990, A. Roig A. (MACN); Villavicencio, 35 F, 8 M, from trap nests, 1225-1259 m a.s.l., D. Vázquez, N. Chacoff & J. Dorado (MACN); 14 km NW El Sosneado, San Rafael, 17-I-2012, D. Medan, ex Proustia cuneifolia (MACN). Neuquén Neuquén: La Lipela, P.N. Nahuel Huapi, 1 M, 9-XII-2000, Medan, Montaldo & Devoto, ex Phacelia sp. (MACN); P.N. Nahuel Huapi, La Lipela, 1 M, 9-XII-2000, Medan et al. (MACN). Salta Salta: San Carlos, 2 M, 4-XI-2004, Compagnucci & Grismado (MACN). San Juan Juan: 1 M, Chiesa Molinari (MLP); Pocito, 1 M, 5-XII-2017, Allasino & Marrero (FAUBA); San Agustín de Valle Fértil, 1 M, 14-XII-1979, A. Roig A. (MACN); Las Tumanas, Valle Fértil, 1 F, 25-I-2010, J.P. Torretta, ex Larrea divaricata (MACN). San Luis: Charlone, 1 M, II-1933, M. Vignatti (MLP); Chosme, 1 F, 16-IX-1941, A. Ogloblin (MLP); Parque Nacional Sierra Las Quijadas, 4 M, 4-5-I-2003, Compagnucci (MACN); San Jerónimo, 3 M, XI-1972, G. Williner (MACN). Santiago del Ester Estero: Desvío 511, Dpto. Matará, 1 F, 24-X-1928, M. Gómez (SEMC). Tucumán ucumán: 1 F, C.S. Reed (MLP); Amaicha del Valle, 2 M, 2-XI-2004, Compagnucci & Grismado (MACN).

Megachile ( Dactylomegachile) tetrazona Friese Megachile tetrazona Friese, 1908: 64, 67 (Holotype male, Argentina (ZMB), examined). Vachal, 1909: 7. Jörgensen, 1909: 214, 215; 1912a: 130; 1912b: 312. Schrottky, 1913a: 248. Moure et al., 2007: 1000. Megachile albopunctata Jörgensen, 1909: 225 (Lectotype female, Argentina, Mendoza, 12-XII-1907, P. Jörgensen, MLP, examined, present designation). Jörgensen, 1912a: 127, 132; 1912b: 310. Schrottky, 1913a: 246. New synonym.

Megachile (Dasymegachile) albopunctata: Toro, 1986: 127. Moure et al., 2007: 963.

Megachile (Chrysosarus) albopunctata: Raw, 2002: 79; 2007: 31. Durante et al., 2008: 432. Megachile (Dactylomegachile) albopunctata: Durante & Cabrera, 2009: 57.

Diagnosis Diagnosis. This species is distinguished by its large size. The female is recognized by its pilosity entirely black, except for the white punctiform tufts behind the pronotal lobe and on the sides of T1 and T2, and the presence of a small cutting edge on the third tooth of the mandible. The male is readily recognized by the bicolored integument of the anterior basitarsus, which is widest basally and tapers apically, having the under surface flattened, glabrous, and polished. The anterior tibial spur has a black apex in both sexes; it is truncate in the male.

Redescription. Female: Body length: 11.5-14.6 mm. Forewing length: 7.9-9.5 mm. Coloration. Integument black except: underside of flagellum and apex of mandible dark brown. Wings weakly infuscate with darker apices; veins and pterostigma brown. Pubescence. Head: entirely black. Mesosoma: entirely black, except white tuft behind pronotal lobe. Disc of scutum with long hairs (1.0-1.3 x MOD), longer on scutellum (1.5-2.2 x MOD). Legs with black hairs, except ferruginous on inner surface of tarsi. Metasoma: with black hairs, except T1-T2 with white punctiform lateral patch; disc of T2-T4 with very short (0.2-0-6 x MOD) hairs, disc of T5-T6 with short and long hairs; T3-T5 with apical hairs not forming bands; scopa black. Structure. Inner margin of eyes nearly parallel, proportion of upper to lower interocular distance 1.1-1.2; interantennal distance 1.2-1.4 x antennocular distance; distance between lateral ocellus and occipital margin 2.6-2.8 x MOD; proportions of scape, pedicel and first three flagellomeres 3.1:1.0:1.0:1.1:1.2; maximum width of gena 0.75 x maximum width of compound eye. Apical margin of clypeus weakly crenulate; fourth mandibular tooth truncate. T6 slightly concave in profile, with rounded apex in dorsal view. Punctation. Clypeus with dense punctures, separated by shiny interspaces 0.1-0.2 x PD, supraclypeal area with tessellate interspaces 0.3-0.6 x PD. Scutum anteriorly and laterally with punctures separated by tessellate interspaces 0.4-1.0 x PD, punctures on center of disc sparser, separated by 1.5-2.5 x PD; scutellum with punctures separated by 0.2-0.5 x PD. Integument of T2-T5 shiny on discs; punctures sparse on T2-T5, on disc of T2 separated by 1.0-2.0 x PD. Male: Body length: 11.6-12.6 mm. Forewing length: 6.9-8.8 mm. Coloration. Similar to that of female, except legs. Foreleg with trochanter, femur and tibia yellowish brown, except dark outer surfaces; basal part of under surface of basitarsus yellowish brown; remainder of leg dark brown to black. Middle and hind legs brown to black, some specimens with yellowish brown areas on femora and sometimes on tibiae. Pubescence. Hairs white on face, lower part of gena and hypostomal areas, brown on vertex (intermixed with white hairs in some specimens), and upper part of gena; mandible with abundant long, brown hairs on basal half. Scutum medially with area of sparse, brown hairs, surrounded by intermixed white and brown hairs; scutellum with brown hairs and metanotum with white hairs. White tufts present behind pronotal lobe and behind tegula; remainder of mesosoma with brown hairs. Foreleg with white hairs on trochanter, basal half of femur, and outer fringe of tarsus (as long as 2.0-2.5 x apical width of basitarsus); inner brush with orange hairs; rest of leg with brown hairs. Mid and hind legs with brown hairs, except inner tarsal brushes orange. T1-T4 with white apical bands, broader laterally; bands entire or interrupted; vestiture on rest of metasoma dark brown. Structure. Lower margin of mandible forming angle near middle. Gena narrower than compound eye (0.73x). Anterior surface of forecoxa with long, abundant hairs, hiding group of weak, yellowish bristles close to spine; spine flattened, 1.1 x MOD; lower outer margins of forefemur and tibia rounded. Anterior basitarsus widest basally at level of distal end of strigillar concavity, then tapering apically; under surface flattened, glabrous, polished; tibial spur truncate, with black apex; proportion of lengths of basitarsus and second tarsomere along midline 1:0.3, basitarsus 5-6 x as long as its apical width. Carina of T6 with median notch; T6 with anterior depression. Pregradular area of S5 with simple hairs laterally, longer apically and shorter, thicker and sinuous basally; postgradular area with short, thick, curved hairs bordering gradulus, medial area with long, simple, stiff hairs forming a median, longitudinal dense brush occupying one fifth of postgradular area; remainder of area with spatulate and simple hairs; without separation area. Lateral pregradular area of S6 with long hairs finely branched apically; central area laterally with simple hairs directed basally, and medially mostly bare, with scattered short hairs; apical lobes large, forming truncate median projection of sternum, with long, simple hairs.

Comments Comments. This species strikingly differs from the other six studied species, which form a morphologically homogeneous group. Noteworthy features are the robustness of the species, the presence of a very small cutting edge on the third mandibular tooth of the female, the shape of the male foretarsus, and the shape and ornamentation of the male metasomal hidden sterna. Distribution. Argentina, provinces of Buenos Aires, Catamarca, Crdoba, La Pampa, La Rioja, Mendoza, Río Negro, San Juan, and San Luis. Chile, Los Andes. Material examined. Argentina. Buenos Air Aires es: Carmen de Patagones, 1 M, XII-1937, M.J. Viana (MACN); Cerro de la Caballada, Patagones, 1 M, 29-II-1937, M.J. Viana (MACN); Felipe Sola, 1 F, XII-1944, A. Martinez (MLP). Catamar Catamarca ca: Las Viñas, 1 M, 9-XI-1942, A. Ogloblin (MLP). Cór Córdoba doba: Tilquicho, 1 F, 20-X-1989, J. Genise (MACN). La Pampa Pampa: Cuchillocó, 1 F, 1913, A. Copello (MACN); Toay, Ea. Anquilóo, 3 F, 15-XI-2008, 15-XI-2009, 12-XII-2009, H.J. Marrero (FAUBA); Toay, Ea. Anquilóo, 3 F, 11-XII-2010, J.P.Torretta (MACN). La Rioja Rioja: Anillaco, 1 M, 1-6-XI-2011, Roig A., González V. & Compagnucci, WPT (MACN); Iliar; 1 F, 30-X-1928, M. Gomez (MACN); Subida a Pampa de la Viuda, Departamento Sanangasta, 1 F, 4-XI-2011, Roig A., Compagnucci & González V. (MACN). Mendoza Mendoza: Reserva Telteca, Lavalle, 1 M, 16-X-2003, G. Debandi (IADIZA); Villavicencio, 2 F, Sitio V1, 32.523139ºS 68.955111ºW, 9-XI-2009, 11-XII- 2009, D. Vázquez, N. Chacoff & J. Dorado (IADIZA); Villavicencio, 1 M, Sitio V4, 32.538722ºS 68.9939611ºW, 4-XII-2007, D. Vázquez, N. Chacoff & J. Dorado (IADIZA); Villavicencio, 2 F, 2 M, Sitio V4, 32.538722ºS 68.9939611ºW, 4-XII-2007, 7-XII-2007, D. Vázquez, N. Chacoff & J. Dorado (MACN); Godoy Cruz, Puesto Chambón, 1 F, 2-XII-1995, G. Debandi (IADIZA); 1 F, C.S. Reed (MLP); Mendoza, 2 M, 20-III-1908, 15-XI-1908, Jörgensen (MLP). RíoRío Negr Negro: Cinchinales, 1 F, 24-XI-1965, Schajovskoi (MLP). San Juan: Pocito, Va. Aberastain, 1 F, XI-19787, J. Garcia (MLP). San Luis Luis: San Jerónimo, 1 M, XI-1972, G. Williner (MACN); D. Donovan, 2 F, 14- XI-1941 (MLP). CHILE. Los Andes: Aconcagua, 2 F, 9- XII-1944, T. Ramírez (MLP).

Megachile ( Dactylomegachile) vagata Vachal

Megachile vagata Vachal, 1908: 228-229 (Syntypes female and male, Mendoza, MNHN, examined). Vachal, 1909: 12. Jörgensen, 1912a: 131, 133, 135; 1912b: 312. Cockerell, 1914: 427; 1917: 240.

Megachile suspecta Vachal, 1909: 12 (Lectotype male, Argentina, Buenos Aires, 9-XI-01, MNHN n° EY6315, examined, pr present esent designation designation). New synonym synonym. Megachile impudens Mitchell, 1930: 288-289, pl. XIV (Holotype female, Argentina, Cordova, Davis, MCZ n° 16204, examined). New synonym synonym.

Megachile ( Dactylomegachile) vagata: Mitchell, 1943: 671. Durante & Cabrera, 2009: 58.

Megachile ( Chrysosarus) vagata: Raw, 2002: 12; 2007: 40. Moure et al., 2007: 960. Durante et al., 2008: 432.

Megachile ( Chrysosarus) impudens: Raw, 2002: 10; 2007: 35. Moure et al., Megachile( Sayapis) suspecta: Raw, 2002: 35.

Diagnosis Diagnosis. This species is close to M. ctenophora, from which it is distinguished by the shorter vestiture in both sexes. Females of M. vagata and M. ctenophora have an orange scopa and the scutum with tessellate integument between punctures, characters shared by M. jenseni, from which they are distinguished by the narrow vertex. Males of M. vagata differ from males of M. infima and M. jenseni in the pilose hypostomal area. Redescription. Female: Body length: 9.5-10.6 mm. Forewing length: 5.6-7.1 mm. Coloration. Integument black except: dark brown on underside of flagellum in some specimens; apex of mandible and claws dark ferruginous (although claws dark brown apically). Wings subhyaline with a light brownish tinge, with darker apices; veins and pterostigma brown. Pubescence. Head: pale specimens with white hairs on paraocular areas and mid part of gena, and intermixed with black hairs on frons; dark specimens with pubescence entirely black. Mesosoma: pale specimens with white patches behind pronotal lobe and above propodeal spiracle; white hairs intermixed with some black hairs on pronotal collar, on scutum, around scutellum, and on posterior surface of propodeum; dark specimens with black hairs, except white patch behind pronotal lobe. Disc of scutum with long hairs (0.8-1.1 x MOD), longer on scutellum (1.2-2.0 x MOD). Legs with black hairs, except ferruginous on inner surface of tarsi. Metasoma: with complete apical bands of white, plumose hairs on T1-T5 (0.5-1.5 x MOD on T1 and T2); discs of T2-T4 with short, erect, black hairs (0.3-0.8 x MOD); T6 with black hairs, in some specimens with some white decumbent hairs. Scopa ferruginous on S2-S6. Structure. Inner margin of eyes slightly convergent below, proportion of upper to lower interocular distance 1.15; interantennal distance 1.4 x antennocular distance; distance between lateral ocellus and occipital margin 1.7 x MOD; proportions of scape, pedicel and first three flagellomeres 3.4:1.0:1.0:1.0:1.1; maximum width of gena 0.9 x maximum width of compound eye. Apical margin of clypeus denticulate; fourth mandibular tooth truncate, weakly incised. T6 slightly concave in profile, with rounded apex in dorsal view. Punctation. Clypeus with dense punctures, separated by shiny interspaces 0.1-0.2 x PD, supraclypeal area with tessellate interspaces 0.2-0.4 x PD. Scutum and scutellum with dense punctures, separated by tessellate interspaces 0.1-0.2 x PD. Discs of T2-T5 tessellate; punctures on disc of T2 small, separated by 0.2-1.0 x PD.

Male: Body length: 9.4-11.4 mm. Forewing length: 5.9-6.9 mm. Coloration. Similar to that of female, except foreleg: under surface of femur and tibia, and entire tarsus ferruginous; underside of second tarsomere with black spot. Pubescence. Hairs long, abundant, yellowish on clypeus, supraclypeal area and paraocular area; whitish on gena, yellowish and white on hypostomal area, dark brown on remainder of head; in some specimens with intermixed white hairs on vertex.

Mesosoma: pale specimens with pubescence entirely white; dark specimens with few intermixed, erect, long, dark brown hairs on scutum and dark brown hairs on mesopleuron below hypoepimeral area, on middle of metapleuron and on lateral side of propodeum. Foreleg: hairs on coxa and trochanter white, on remainder of leg mostly orange and white, except tibia with short dark hairs on dorsal and outer surfaces; outer fringe of tarsus with orange hairs ventrally and covered with shorter white hairs dorsally. Middle and hind legs mostly with dark hairs, except middle tarsus with hairs paler. Metasoma: T1 with long, white hairs on disc and defined white apical band; T2-T4 with black hairs on discs and white, complete apical bands. T5 variable, with or without white apical band, sometimes with basal decumbent white hairs. T6 with black hairs. Structure. Lower margin of mandible forming triangular projection near middle. Hypostomal area pilose. Gena wider than compound eye (1.1:1.0). Anterior surface of forecoxa with sparse punctures bearing minute hairs, and group of 15-20 ferruginous bristles in front of coxal spine; spine of moderate length, 0.75 x MOD; lower outer margin of forefemur and tibia rounded. Anterior basitarsus flattened, proportion of lengths of basitarsus and second tarsomere along midline 1:0.75, basitarsus 1.8 as long as its apical width. Carina of T6 with small median notch and laterally with 4-5 spiniform teeth; T6 with weak median depression above carina. Pregradular area of S5 with simple hairs laterally; postgradular area with medial area of stiff, basally thickened hairs, and remainder of area with simple hairs; separation area narrow, traslucent (Fig. 1D). Lateral pregradular area of S6 with long hairs finely branched apically; central area bare medially and laterally with simple hairs directed mesally; apical lobes glabrous, short, subtriangular (Fig. 1D). Comments Comments. This species has been reared from trap nests in three localities (Carlos Casares, province of Buenos Aires, Toay, province of La Pampa, and Villavicencio, province of Mendoza). Distribution. Argentina, provinces of Buenos Aires, Catamarca, Córdoba, Jujuy, La Pampa, La Rioja, Mendoza, Río Negro, Salta, San Juan, San Luis, Santiago del Estero, and Tucumán. Uruguay, departments of Canelones, Montevideo and Río Negro. Material examined. Argentina. Buenos Air Aires: es: Bahía Blanca, 3 M, 2 F, 27-I/1-II-2016, S.C. Villamil (MACN); Ciudad Autónoma de Buenos Aires, 2 M, 29-I-1906 & 21-XII-1908, J. Brthes (MACN); Campo de Mayo, 2 M, I-1920, M. Gómez (MACN); Palermo, 1 M, III-1917, Bosq (MACN); Lomas, 1 M, X-1917 (MACN); San Antonio de Padua, 3 F, 21-XI-2003, M.F. Rodríguez (MACN); Claromecó, Partido Tres Arroyos, 1 F, 2-III-2006, A. Roig A. (MACN); Mar del Plata, 1 F, XII-2003, R. González Vaquero (MACN); La Plata, 1 F, XII-2005, F. Vossler (MACN); General Conesa, 3 F, 2 M, 26-XII-1952, Senkute (SEMC); Villa Elisa, 1 F, II-1955, J. Foerster (SEMC); Mar de Ajó, 1 M, 15-25-XII-1952, M. Senkute (SEMC); San Clemente del Tuy, 1 F, 22-XI-1951, J. Forester (SEMC); González Catán, 2 F, II-1952, Foerster (SEMC); Tigre, 1 F, 3-10-XI-1956 (SEMC); Lavallol, 4 F, 20-II-1952, M. Senkute (SEMC); Carlos Casares, Ea San Claudio, 1 F (reared from trap-nest), 13-II-2011, J.P. Torretta (FAUBA); Ciudad Autónoma de Buenos Aires, Jardín Botánico Facultad de Agronomía, 1 F, 30-XI-2007, J.P. Torretta (FAUBA); Va. Devoto, 2 M, 1 F, 8-I-1941, A. Ogloblin (MLP); Va. Devoto, 1 F, 27-XI-1927, S.J. Gomez (MLP); Henderson, 1 F, 15-XII-1974 (MLP); H. Ascasubi, 1 M, 18-XII-1974 (MLP); Trenque Lauquen, 2 F, 6 M, 13-XII-1974 (MLP); José C. Paz, 1 F, 1 M, 10-I-1940, A. Ogloblin (MLP). Catamar Catamarca: ca: 20 km N Andalgalá, 1 M, 27-XII-1971, D. Brothers (SEMC). Cór Córdoba doba: Chancaní, 2 M, 10 F, X-1991, Genise, Farina & Hazeldine (MACN); Chancaní, 1 F, X-1987, J.Genise (MACN); ciudad de Córdoba, 1 F, II-1975, G. Williner (MACN). Jujuy: San Salvador de Jujuy "en casa", 1 F, 2 M, XII-1903, E.L. Holmberg (MACN). La Pampa: Toay, Ea. Anquilóo, 2 M, 2 F, 29-X-2011 (reared from trap-nests), J.P. Torretta (FAUBA); Toay, Ea. Anquilóo, 2 M, 11-XII-2010, J.P. Torretta (FAUBA); Toay, Ea. Anquilóo, 1M, 10-XI-2008, H.J. Marrero (FAUBA); Toay, Ea. Anquilóo, 2 F, 10-II-2010, ex Baccharis ulicina, H.J. Marrero (FAUBA); Santa Rosa, 1 F, III-1939, T. Aramendia (MACN); Cuchillocó, 1 F, 1913, A. Copello (MACN). La Rioja Rioja: 20 Km N Chepes, 1 F, 11-X-1997, S. Roig (IADIZA); 10 Km S Vinchina, 1 F, 13-X-1997, S. Roig (IADIZA); 16 M, 3 F, Giacomelli col., cat. nº 11765 (MACN); ciudad La Rioja, 1 F, Giacomelli (MACN); Jagüel, 1 F, 22-I-2006, L. Compagnucci (MACN); Anillaco, 1 F, 29-X-2011, P. Fidalgo (MACN); Iliar, 4 F, 1 M, 30-X-1928, M. Gómez (SEMC). Mendoza: Lavalle, Reserva Telteca, 2 F, 16/ 25-X-1997, S. Roig (IADIZA); Lavalle, Reserva Telteca, 1 M,16-II-1998, S. Roig (IADIZA); Godoy Cruz, Pto. Chambón, 1 F, 2-XII-1995, G. Debandi (IADIZA); El Salto, Departamento Luján, 1 M, 21-XII-1995, A. Roig A. (MACN); Potrerillos, 1 M, I-1974, A. Roig A. (MACN); Villavicencio, 4 F, 1 M, reared from traps, D. Vázquez, N. Chacoff & J. Dorado (MACN); Mendoza, 10-XI-1906, Jörgensen (MLP). Rio Negr Negro: Cipolletti, 1 F, III-1957, E. Fleiss (MLP); Río Colorado, 2 M, II-1943, JMB (MLP); Río Colorado, 1 M, 18-II-1913, Jörgensen (MLP). Salta: Cerrillos, INTA, 1 M, 21-X-1994, P. Hoc (MACN); 5 km NE Cafayate, 8 F, 2 M, 14-XI-1993, A. Roig A. (MACN); 1 F, 2-XI-1912 (MLP). San Juan: San Juan, 1 F, X-1941, Chiesa Molinari (MLP); 1 M, 29-XI-1922, M. Gómez (MACN). San Luis: Potrero de los Funes, 1 F, 20-I-1926, M. Gómez (MACN). Santiago del Ester Estero: o: Beltrán, 1 M, 7-XI-1940, Maldonado (MLP); Colonia Dora, 1 F, X-1956 (SEMC). Tucumán: ucumán: Amaicha del Valle, 1 F, 2-II-1987, L. Moffatt (MACN); Tapia, 25 km N Tucumán, 10-XII-1971, D. Brothers (SEMC); Benjamín Paz, 1 M, 19-I-1951, A. Ogloblin (MLP). URUGUAY. Canelones Canelones: Pº de Falzón, 1 F, 6-IV-1923 (MACN). Montevideo: Montevideo, 25-II-1909, J. Brèthes (MACN); Pocitos, 1F, 22-XI-1951, C. Carbonell (MLP); Peñarol, 1 F, 5-XII-1931 (MLP). Río Negr Negro: 1 F, Menafra, 10-XII-1914 (MACN).

Key to species included in this study Females

1. Vertex broad, distance from lateral ocellus to posterior margin of head 2.1-2.8 x MOD ..................... 2. 1’. Vertex narrow, distance from lateral ocellus to posterior margin of head 1.5-1.9 x MOD .................... 4. 2. Disc of scutum with punctures irregularly spaced, separated by 0.5-3.0 PD. Scopa black. Vestiture black, except white punctiform tufts below tegula and laterally on T1 and T2 ............................................. M. tetrazona. 2’. Disc of scutum with punctures dense, evenly spaced, separated by 0.3-0.5 PD. Scopa yellowish or orange (black in few Patagonian specimens). T1 and T2 usually with white apical bands either complete or interrupted (never punctiform), but entirely black in some Patagonian specimens ...................................... 3. 3. Anterior margin of clypeus medially smooth, without denticles. Basal tooth of mandible pointed. Scopa yellowish ....................................... M.leucografa. 3’. Anterior margin of clypeus denticulate, although sometimes denticles weak. Basal tooth of mandible truncate. Scopa varying from orange on S2-S6 to entirely 4. Apical margin of S2-S5 with lateral hair fasciae beneath scopa. Outer surface of hind tibia with white hairs. Small species, 6.7-9.4 mm long ............ M. infima. 4’. Apical margin of S2-S5 without lateral hair fasciae beneath scopa. Outer surface of hind tibia with black hairs. Larger species, 9.2-12.0 mm long .................... 5. 5. Disc of scutum with punctures separated by smooth, shiny interspaces 1.0-1.5 PD. Scopa black ...... ........................................................................ M. binota. 5’. Disc of scutum with punctures separated by tessellate interspaces 0.10-0.25 PD. Scopa usually orange or black and orange, but entirely black in some Patagonian specimens ............................................... 6. 6. Disc of T2-T4 with long erect hairs of nonuniform length, between 1.0-2.0 x MOD ............. M. ctenophora. 6’. Disc of T2-T4 with short erect hairs of nonuniform length, between 0.3-0.8 x MOD .................... M. vagata. Males 1. Preapical carina of T6 with distinct median emargination, and at each side of it at most undulate ...... ...................................................................................... 2. 1'. Preapical carina of T6 conspicuously denticulate, with or without median emargination ........................... 3. 2.- Lower margin of mandible with basal, dense tuft of hairs. Foretarsus with basitarsus broadened (1.5x as long as apical width), hairy on under surface, with large outer fringe; second tarsomere with distinct black spot on underside; tibial spur with yellowish apex ............ .................................................................. M. leucografa. 2'. Lower margin of mandible with abundant hairs, but not forming a tuft. Foretarsus with basitarsus slender (5-6x as long as apical width), broader basally and tapering apically, with glabrous under surface, with small fringe; second tarsomere entirely black; tibial spur truncate, with black apex ........................... M.tetrazona. 3. Hypostomal area with glabrous, smooth and shiny area. Preapical carina of T6 without median emargination ................................................................. 4. 3’. Hypostomal area pilose. Preapical carina of T6 with median emargination ........................................... 5. 4. Lower margin of mandible concave, forming triangular projection near basal third. Large species, 10.2-11.5 mm .................................................. M.jenseni. 4’ Lower margin of mandible with angle near middle. Small species, 5.3-7.5 mm .............................. M.infima. 5. Disc of T2-T4 with long, erect hairs of nonuniform length, between 0.9-1.1 x MOD ............. M. ctenophora. 5’. Disc of T2-T4 with short, erect hairs of nonuniform length, between 0.4-0.5 x MOD .................... M. vagata. This article has been registered in the Official Register of Zoological Nomenclature (ZooBank) as [urn:lsid:zoobank.org:pub:61C28B44-0212-48FD-B605- 8C68B0630EA6]. DURANTE, S.P. et al. Megachile ( Dactylomegachile) in Argentina 32

Fig. 1. Male metasomal sterna 5 (left half) and 6 (right half) in ventral views. A. M. infima. B. M. jenseni. C. M. ctenophora. D. M. vagata. Scale = 0.5 mm

 

ACKNOWLEDGEMENTS

We thank S. Roig Juñent (IADIZA, Mendoza), S. Cover (MCZ, Cambridge), C. Villemant (MNHN, Paris), D. Notton (NHMUK, London), M. Engel (SEMC, Lawrence), and F. Koch (ZMB, Berlin) for the loan of specimens. We thank Cecilia Gorretta for her help with the drawings of male sterna and two anonymous reviewers for their useful comments and corrections on the manuscript.

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